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Mind Reader?
When it comes to using a brain monitor to measure consciousness during surgery, everybody has an opinion. What's yours?
Outpatient Surgery Editors
Publish Date: October 10, 2007   |  Tags:   Anesthesia

Should there be a brain monitor in every OR? The answer is no, at least not yet, for 58 percent of you surveyed. The American Society of Anesthesiologists agreed, declining to make monitors the standard of care when it approved the group's first standards on preventing intraoperative awareness at its annual meeting last month. Instead of putting its collective muscle behind the technology, the ASA's house of delegates gave monitors a tepid endorsement, approving a practice advisory that leaves to individual practitioners the decision to use the technology. But for the manufacturer of the Bispectral Index monitor, for the loyal legion of clinicians who swear by the machine's ability to precisely measure consciousness during surgery and let them deliver a better anesthetic, and for those patients who've experienced intraoperative awareness, the answer is yes. What's your call?

Measuring the target organ
Aspect Medical's BIS machine, as the monitor is commonly called, is already installed in about 40 percent of U.S. operating rooms. Aspect has about a 90 percent share of the market for the devices, which sell on average for about $4,000 to $5,000 (sensors required for each procedure cost between $13 and $25). Our survey of more than 300 readers (n=337) corroborated those numbers, finding that 38 percent of outpatient surgery facilities (n=120) have consciousness monitors, and nearly all of these monitors are BIS monitors.

"The brain is the target organ for anesthesia. The traditional signs of depth of sleep - heart rate, blood pressure, breathing rate, tearing, grimacing, movement and so forth - upon which I relied for the first 22 years of my career, do not measure the target organ," says anesthesiologist Barry L. Friedberg, MD, of Corona del Mar, Calif. "Anesthesia is sometimes defined as the art of the controlled overdose. Knowing that the traditional signs may be inaccurate, anesthesiologists are obliged to routinely over-medicate for fear of under-medicating."

For the 58 percent (n=184) of facilities whose ORs aren't equipped with consciousness monitors, the overriding feeling is that there is little to no need for monitoring in the outpatient setting. Many, like San Diego anesthesiologist Adam F. Dorin, MD, MBA, believe practitioner expertise is the real key to anesthesia success.

"In the usual, non-cosmetic outpatient type of case where the patient is under conventional, balanced general anesthesia - orthopedic, GYN, general surgery and ENT, for example - the most valuable tool for giving anesthesia is experience," says Dr. Dorin. "It is my experience, not a consciousness monitor, that has allowed smooth anesthetics and smooth wake-ups. It is about training, years in practice and solid intuitive judgment. I have yet to be convinced that this generation of BIS-type monitoring will ever reach the threshold of necessary or indispensable."

While at least one study has found the devices to be effective, others have reached a different conclusion, say ASA members. The ASA cited "insufficient evidence to justify a standard, guidelines or absolute requirement that these devices be used,'" when it declined to recommend routine consciousness monitoring to reduce awareness. Instead, the society recommended relying on "multiple modalities" such as clinical signs and conventional monitoring, and the ASA's president suggested that the most important monitor is the "anesthesiologist himself."

The ASA says doctors can consider the devices on a case-by-case basis - particularly in trauma surgeries and Caesarean sections, which are two procedures in which deep anesthesia is often avoided and partial awareness is most likely.

Do You Use a Consciousness Monitor?

Aware of awareness
Level-of-consciousness monitoring surfaced in 1996 when the FDA gave approval for the Bispectral Index monitor to measure the level of patient hypnosis. Nearly 10 years later, anesthesia awareness has ignited the debate over how necessary consciousness monitoring is to prevent patients from waking up during surgery, which occurs in one or two cases out of every 1,000. The phenomenon has been widely publicized by patient lawsuits and the horrifying stories of patients who could feel and hear their surgeries but couldn't cry out or move. We can also trace the heightened focus on awareness to two events:

  • In the fall of 2003, the FDA approved a labeling change that let Aspect use a new phrase in its marketing materials that said its monitors "may be associated with the reduction of the incidence of awareness with recall in adults during general anesthesia and sedation."
  • The Joint Commission on Accreditation of Healthcare Organizations issued an alert in October 2004 aimed at reducing anesthesia awareness, calling it a "frightening phenomenon" that is "underrecognized and undertreated." JCAHO estimated that, every year, between 20,000 and 40,000 patients undergoing surgery in the United States "wake up" during the procedure.

Benefits of Consciousness Monitoring

Improves safety of anesthesia care


Reduces anesthesia awareness


Reduces the number of problem cases in which patients become over-sedated and require long recovery time


Reduces inhalational agent consumption


Reduces propofol consumption


SOURCE: Outpatient Surgery Magazine Reader Survey, n=99

Some of our panelists resent the recent focus on anesthesia awareness by medical societies and other bodies. "JCAHO is reactionary and jumps on topical issues," says one Washington-based anesthesiologist. "Their emphasis [on anesthesia awareness] is nothing more than what most conscientious anesthesiologists already do, and for them to codify it is not really helpful. It leads to over-interpretation and over-emphasis."

In its directive, JCAHO instructed doctors to discuss the risk of anesthesia awareness with patients before surgery - and to apologize when patients experience anesthesia awareness. It did not endorse the use of brain activity monitors but noted that the FDA issued a favorable review of the Bispectral Index monitor.

Indications for Consciousness Monitoring

General anesthesia/inhalational agents


History/risk of anesthesia awareness






Patients with neurological impairment




SOURCE: Outpatient Surgery Magazine Reader Survey, n=97

Drawbacks of Consciousness Monitoring

Too costly


Not reliable/predictable


Clinically ineffective


Lag time reduces practical benefit


Too difficult to use


SOURCE: Outpatient Surgery Magazine Reader Survey, n=112

Clinical studies promoted by Aspect Medical suggest that BIS monitoring can reduce awareness with recall in patients who receive general anesthesia and muscle relaxants by as much as 77 percent and in patients at high risk for awareness by as much as 82 percent.

Nassib Chamoun, the president and CEO of Aspect, calls the ASA's practice advisory on awakening "a significant step forward in addressing intraoperative awareness and the role of brain function monitoring."

Still, for our panelists who do use consciousness monitors, clinical utility can often take a back seat to practical concerns. What matters more to these practitioners is the knowledge and appearance that they're using every available tool to reduce this rare but potentially terrifying occurrence. Several panelists note that the monitors can allay patients' very real fears that they'll awaken during surgery and even reduce "psychological trauma."

Others point to litigation prevention. Lou Ann Bowen, BA, director of anesthesia and surgery with Montgomery General Hospital in Montgomery, W. Va., sums it up this way: "The issue of awareness under anesthesia is getting much more media attention. In a case in which the patient does have awareness under anesthesia, monitoring shows you did your best to prevent this unfortunate occurrence and may be advantageous in the event of litigation."

On the Web

Tour Aspect Medical Systems' customer education Web site at www.biseducation.com.

Sketchy science and skeptical docs
Aspect Medical has pushed for its machines to become a standard feature in operating rooms, but some doctors have resisted, saying clinical evidence of the monitors' effectiveness was lacking.

The BIS monitor tracks brain-wave activity and provides doctors a reading that represents the mathematical probability the patient is wide awake. Using a sensor placed on the patient's forehead, BIS monitoring translates information from the electroencephalogram into a single number that represents the patient's level of consciousness. This number - the BIS value - ranges from 100 (indicating an awake patient) to zero (indicating the absence of brain activity). Using the BIS value in conjunction with other vital signs to guide administration of anesthetic medication lets clinicians make better-informed decisions to achieve optimal anesthesia.

"BIS is clearly not perfect for every patient, but it gives us valuable information that we can get from no other source," says Dr. Friedberg. "Vital signs like heart rate and blood pressure are notoriously unreliable signs of depth of anesthesia."

Hospira, one of the largest hospital products manufacturers in the United States, hopes to challenge Aspect in the monitoring market. Last July, Hospira purchased Physiometrix, whose portfolio includes the PSA 4000, a real-time brain-state monitor, and the SEDLine monitor (previously known as the PSA 5000).

Our survey findings
At the heart of the issue, consciousness monitors are largely a matter of preference. Most outpatient surgical facilities don't have one, and practitioners who do use them cite reasons that vary from patient safety to liability protection to public relations. Here is an in-depth look into how our readers view consciousness monitoring.

According to our survey, 38 percent of outpatient surgery facilities (n=120) have consciousness monitors. While the indications for monitoring vary, two-thirds use the technology for patients who receive general inhalational anesthesia, and more than half (58 percent) use them for patients with a history or risk of anesthesia awareness. Forty-seven percent also monitor elderly patients routinely, and about two-thirds use consciousness monitoring for TIVA cases, patients with neurological impairment and pediatric patients. A smaller number reserve consciousness monitoring for longer cases (1.5 hours or longer), patients with conditions that put them at an increased risk from heavy anesthesia (hypotensive patients, for example) or morbidly obese patients.

"Lean body weight is not easy to calculate in morbidly obese patients, so I typically administer a TIVA regimen to these patients and titrate it to the consciousness monitor," says one New York-based CRNA. "For instance, I would anesthetize a gastric bypass patient with propofol/remifentanil or propofol/ketamine, and titrate the propofol to the BIS and the analgesia to the blood pressure and heart rate."

Adds Shawn Marsh, MD, with the Colorado-based Littleton Hospital: "It helps me deliver a better titrated anesthetic. This is especially useful for elderly or unstable patients ' The MAC of desflurane in a 70-year-old is around 2 percent, but who would actually run that light unless you knew that the patient was actually asleep?" Dr. Marsh also cites the clinical utility of knowing the level of consciousness independent of vital signs, given the trend to put patients on beta-blockers pre-operatively, which reduces reliability of heart rate and blood pressure indicators.

Satisfaction with Consciousness Monitors?
For 63 percent of our panelists who use consciousness monitors, patient safety is the most important benefit. Protection against anesthesia awareness runs a close second. For many users, the simple fact that they can show patients they're making every effort to prevent intraoperative awakening is worth the added cost of monitoring.

"This greatly relieves patient anxiety that they will awaken during the procedure," says Maggie Murphy, RN, CNOR, surgical services manager with Memorial Community Hospital in Edgerton, Wis. "We had a patient who watched a TV talk show when awareness was everywhere in the news. Because we had the monitor, we were not only able to reassure her but we also showed her that we used the latest technology, even though we are small."

Adds Cheryl Stanley, RN, CASC, the director of the Elkhart Clinic Endoscopy & Surgery Center in Indiana: "This is great public relations with patients. They feel more secure having surgery knowing a monitor will be used." Quite a few panelists also cited protection against awareness litigation as a primary reason for using consciousness monitors.

Other benefits reported less often by our panelists who use consciousness monitors include less over-sedation, reduced inhalational agent and propofol requirements, and shortened PACU time. "The greatest benefit is the ability to titrate the anesthetic level during the last 15 to 20 minutes of a case, and allow the patient to emerge more quickly without concern over awareness," says Ms. Bowen. At the Baltimore, Md.-based Franklin Square Hospital Center, director of perioperative information technology Chet Wyman, MD, says his facility has saved about $100,000 annually on inhalational agents since consciousness monitors came on board nine years ago. Adds Michael Barts, CRNA, with Northern Montana Hospital in Havre, Mont.: "I use it as a tool to allow faster wake-ups and turnover times for the OR. I easily save five minutes per general anesthetic wake-up and removal of the LMA or ET tube."

Not convinced
Jan Mannino, CRNA, JD, administrator and anesthetist at the OCSC in Santa Ana, Calif., is not convinced that a consciousness monitor is worth the cost. "My anesthesia technique is to administer anesthesia to the patient and not treat the numbers on a monitor," she says. "In 45 years, I haven't had a patient complain of recall. I make it part of my post-op visit to ask them the last thing they remember before going to sleep and the first thing they remember post-op. I do think these monitors have a place in trauma, in open heart surgery and for patients who are in shock and need minimal anesthesia. None of these are cases that would be performed in the outpatient surgical setting."

A large portion of our non-users (60 percent) also view cost as a significant drawback of consciousness monitors. The monitors don't provide enough benefit to justify an additional average cost of $15 to $18 per case, they say, and sometimes don't provide any benefit at all. More than two-thirds of non-users view consciousness monitors as unreliable or unpredictable, and 19 percent say they're clinically ineffective.

"It did not correlate with the patient," says Doug Yunker, MD, the medical director at Upper Arlington Surgery Center in Columbus, Ohio. "When the monitor showed the patient was light, this usually correlated with patient movement. Also, artifacts and Bovie interference made use of BIS difficult."

Some research bears this out; studies show that muscle activity and electric device interference can create artifacts that skew the reading, and that readings can vary widely from one patient to another. In addition, one new study shows that intra-abdominal irrigation can cause a marked decrease in the BIS reading. Adds Jeffrey D. Weertman, MHS, CRNA, of Clearwater Anesthesia, PLLC, in Fort Worth, Texas: "I feel that the consciousness monitor technology is not yet advanced enough or reliable enough to be placed on the same level of other standardized monitors. They are expensive and at times give erroneous information."

Eye of the beholder
Our survey results suggest that the value of consciousness monitoring is in the eye of the beholder. "As with any monitor, it is a technical device that depends on the way it is applied, the interpretation of the user and the type of anesthesia used," says Ann Sikes, RN, CRNA, APRN, with the Shelton, Conn.-based Bridgeport Hospital, a non-user who feels the consciousness monitor does not provide her value over and above the standard EKG monitor and BP cuff. "Our newer gases and IV medications have helped diminish recall more than any monitor," she says.

Ultimately, however, those who perceive value to consciousness monitoring are finding ways to work around their shortcomings, and they believe the devices are worth the effort. Seventy percent of users who responded to our survey say they are "satisfied" or "very satisfied," while only 12 percent express dissatisfaction.

"There is definitely a learning curve, and providers have to commit to learn the technology," says Littleton Hospital's Dr. Marsh. "They must especially focus on the interpretation of artifact and the issue of patient movement with painful stimuli, even at deep states of consciousness." Concludes Dean Mazurek, CRNA, of Mercer Medical Center in Trenton, N.J.: "Some of my peers feel that my use of consciousness monitoring is a weakness or lack of confidence in my overall technique. This is not the case, and I am simply considering the fact that I want to give my patients the best care possible."